Abstract: The invention generally concerns the production of defective Adenovirus helper viruses for producing a recombinant adeno-associated virus (rAAV), wherein the Adenovirus helper virus contains at least one mutation selected from (a) an inactivating mutation in the transcription unit coding for the L4-100K protein; (b) an inactivating mutation in the transcription unit coding for the L1-52/55K protein; (c) an inactivating mutation in the transcription unit coding for the preterminal protein (pTP); (d) a mutation in the L4-100K protein in order to render it temperature-sensitive (ts); (e) a mutation in the hexon protein in order to render it temperature-sensitive (ts); and/or (f) a mutation in the L4-00K protein and a mutation in the hexon protein in order to render it temperature-sensitive (ts).